The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Automotive vehicles include rotary shafts that are at least partially received in and rotate relative to a stationary housing. Examples of such arrangements are found in conventional transmissions and axle assemblies. It is necessary to provide a seal at the interface between the shaft and the housing. Sealing the interface is necessary because under many driving conditions, especially during rain, large amounts of contaminants are present that could enter into the interface between the shaft and the housing and cause eventual problems. Conventional sealing arrangements typically include a rubber lip seal to prevent contaminants from entering into the system. Further, the rubber lip seals are used to keep lubricant from exiting the system.
There are several problems with conventional rubber lip seals. First, rubber lip seals tend to wear out in an undesirable fashion. The rotary shafts on most vehicles rotate at very high speeds and the constant contact between the rotating shaft and the rubber lip seal causes the seal to wear. Furthermore, the presence of contaminants along the contact area between the shaft and the rubber lip seal often cause significant wear on the seal, which results in short seal life.
A further problem exists in that the rotary shafts have some radial and axial movement relative to the housing. With conventional lip seals, such movement is not compensated for and, a proper seal is not maintained. Under these conditions, it is more likely that outside contaminants will enter into the shaft and housing interface, and, moreover, become lodged between the lip seal and the shaft which results in faster wear-out of the seal.